A multiplex or mux (called virtual sub-channel in the United States and Canada, and bouquet in France) is a grouping of program services as interleaved data packets for broadcast over a network or modulated multiplexed medium. The program services are split out at the receiving end. In the United Kingdom, a terrestrial multiplex (usually abbreviated mux) has a fixed bandwidth of 8 MHz CODFM of interleaved H.222 packets containing a number of channels. In the United States, a similar arrangement using 6 MHz 8VSB is often described as a channel with virtual sub-channels. Pay television multiplexes In regards to television, the term multiplex is often used to refer to a single broadcaster offering multiple channels of programming as a single bundle to its subscribers. The term is most synonymous with premium television services, such as those devoted to films (where the term evokes the symbolism of multiplex cinemas) or sports; for instance, film services may operate multiplex channels devoted to specific genres and traits (such as action, classic, comedy, drama and romance, or family films) alongside their primary flagship channel, while sports services may place specific events or sports on specific channels. Multiplex channels are not necessarily sold separately on an a la carte basis from their parent and sister channels. Digital subchannels Analog television channels, whether terrestrial, cable or satellite, are transmitted as a single program service uncompressed at the same fixed bandwidth, which fills the entire bandwidth available. Digital television channels can be interleaved and are in a highly compressed format, so that the bandwidth they require varies due to the bitrate provided to each channel; it is more cost efficient to transmit several channels together so that they share the same bandwidth, each channel has carefully constrained bitrates allocated, so that the sum of all channels fill the fixed bandwidth provided. A group of program services transmitted within a particular bandwidth allocation is erroneously known as a multiplex; or the channels may be called subchannels. Sometimes, when analog transmissions are replaced by digital, the fixed bandwidth of one analog broadcast is allocated to the program services; the bandwidth of one analog broadcast is sufficient for several compressed channels. A set-top box or integrated digital television is required to tune in, receive, and split a channel for viewing. An H.222 transport can contain (depending on the bit-rate available) half a dozen television channels yet uses the same space